Real-time spectrum analyzers such as the RSA6100 and RSA3400 families available from Tektronix, Inc. of Beaverton, Oreg. trigger on, capture, and analyze RF signals in real-time. These test and measurement instruments seamlessly capture RF signals so that, unlike conventional swept spectrum analyzers and vector signal analyzers, no data is missed within a specified bandwidth.
An experienced user can look at a display of a real-time spectrum analyzer and recognize different types of signals based on their visual appearance. For example, an experienced user can observe a signal's bandwidth, duration, amplitude or power, the number and shape of its spectral lobes, and other visual clues, and based on that, determine whether the signal is modulated according to a particular modulation standard, whether the signal was transmitted by a particular transmitter, and so on. The user may then use that information to select an appropriate measurement for the signal.
However, requiring a user to recognize a signal can be time-consuming and inconvenient for the user. Furthermore, in some cases, an inexperienced user may need to identify a signal but lack the expertise to do so.